The present invention relates generally to protective latch guards for use with locks installed in doors and, more particularly, to a latch guard that protects a lock latch against tampering and that limits separation of the door from an adjacent door or door frame.
A typical door lock prevents unauthorized entry through a door by extending a latch between the door and an adjacent door or door frame. However, this type of lock can be defeated, for example, by inserting a saw or other cutting device into the space between the door and the adjacent door frame and severing the latch where it extends through this space. The latch also can be defeated by inserting a crowbar or the like into the space above the latch and then bending the latch down by pounding on the crowbar with a hammer. One solution to the problems has been to permanently mount a cover plate over the space between the door and the adjacent door frame in the area of the latch.
However, the installation of a permanently installed cover plate can be particularly troublesome with so-called center hung glass doors that typically swing in and out and include a relatively narrow, hollow aluminum frame or stile. In general, the locking mechanism in these doors is installed in the interior of the hollow door stile with a raised cylinder having a key hole accessible through its front wall. Adjacent the glass door is a door frame or another center hung glass door. Since the center hung door generally swings in and out, a permanently installed cover plate would prevent the door from swinging in or prevent an adjacent door from swinging out. Thus, the latch guard should allow the door to swing unrestricted and not interfere with the door's normal operation.
Accordingly, one solution for double swinging glass doors has been to use a retractable shutter plate mounted on the stile of one door that links to another cover housing mounted on the other door. The shutter plate is engaged using a special key just before the door is locked. However, latch guards of the shutter plate type, although somewhat effective, are not entirely satisfactory. For example, installation requires that a number of holes be drilled into the stiles to accommodate the primary and secondary housings and the shutter assembly. Moreover, the shutter plate does not prevent door spreading. Also, shutter plate covers are expensive from a complexity and cost of materials standpoint.
Accordingly, there has existed a definite need for a latch guard adapted for use on inwardly and outwardly swinging narrow stile doors that allows the door to be easily opened and closed without interfering with its normal operation and that prevents tampering with the lock latch and spreading of the door frame. The present invention satisfies these needs and provides further related advantages.